Subpectoral Biceps Tenodesis with a Bicortical Button and Proximity to the Axillary Nerve: An Anatomical Study

Background/Objectives: Subpectoral biceps tenodesis using a bicortical button has been associated with the risk of damage to the axillary nerve. The purpose of this study is to describe the anatomical relationships between the long head of the biceps tendon tenodesis location, the bicortical tenodesis button, the pectoralis major tendon, and the axillary nerve to help clarify the safety of using bicortical button fixation. Methods: Subpectoral biceps tenodesis with a bicortical button was performed on ten cadaveric shoulders. The specimens were dissected to identify the tenodesis button, the pectoralis major tendon, and the axillary nerve. Distances were measured between the anterior cortical drill hole and the proximal border of the pectoralis major tendon and between the tenodesis button and the axillary nerve. Results: The distance between the tenodesis button and the axillary nerve demonstrated a very high positive and statistically significant correlation with the distance between the anterior cortical drill hole and the proximal border of the pectoralis major tendon (R = 0.9586, p = 1.22 × 10 −5). Conclusions: The proximal border of the pectoralis major tendon correlates with the level of the anterior branch of the axillary nerve. Subpectoral biceps tenodesis using a bicortical button is a safe procedure with regard to the axillary nerve given it is performed well below the proximal border of the pectoralis major tendon. The inferior border of the pectoralis major tendon is a useful intraoperative landmark.